Eric Mele gives us an overview of a parallel rack refrigeration system. He shows and describes the components of a grocery rack.
Parallel rack refrigeration systems have multiple compressors that are all tied together in parallel. So, the discharge and suction are all tied in together. Each compressor’s discharge line will drop down into one main discharge line. That main discharge line has an oil separator, which returns the oil to the reservoir and allows the refrigerant to proceed to the condenser outside the rack room.
The refrigerant liquefies in the condenser and comes out via the liquid line. Refrigerant in the liquid line goes to the receiver, which is located underneath the compressors in this system but can be remote as well. The refrigerant then goes through the liquid line drier and to the remote liquid header. The liquid goes down to all of the cases and loads beneath the rack room, which are often walk-in refrigerators (where the heat absorption happens).
Behind the liquid header, we have suction lines with EPR valves. These EPR valves are electronic, which regulate the suction gas to achieve 100% runtime between defrosts. The suction lines all tie together into a common suction header, which then ties into the suction side on each compressor.
The oil separator and reservoir are critical components of rack refrigeration systems. The oil reservoir must be able to supply oil across three (or more) compressors.
Overall, the goals of a rack refrigeration system are to keep compressors running as long as possible, share the refrigerant charge, share the load, and try to achieve 100% runtime between defrosts.
Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.
Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.
Parallel rack refrigeration systems have multiple compressors that are all tied together in parallel. So, the discharge and suction are all tied in together. Each compressor’s discharge line will drop down into one main discharge line. That main discharge line has an oil separator, which returns the oil to the reservoir and allows the refrigerant to proceed to the condenser outside the rack room.
The refrigerant liquefies in the condenser and comes out via the liquid line. Refrigerant in the liquid line goes to the receiver, which is located underneath the compressors in this system but can be remote as well. The refrigerant then goes through the liquid line drier and to the remote liquid header. The liquid goes down to all of the cases and loads beneath the rack room, which are often walk-in refrigerators (where the heat absorption happens).
Behind the liquid header, we have suction lines with EPR valves. These EPR valves are electronic, which regulate the suction gas to achieve 100% runtime between defrosts. The suction lines all tie together into a common suction header, which then ties into the suction side on each compressor.
The oil separator and reservoir are critical components of rack refrigeration systems. The oil reservoir must be able to supply oil across three (or more) compressors.
Overall, the goals of a rack refrigeration system are to keep compressors running as long as possible, share the refrigerant charge, share the load, and try to achieve 100% runtime between defrosts.
Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.
Learn more about the 2022 HVACR Training Symposium at https://hvacrschool.com/symposium/.
This is going to be a basic overview of parallel rack refrigeration and we're going to define what parallel rack refrigeration is here. So all three of these compressors on this rack are piped together in parallel, which means the discharge and suction are all tied together. These discharge lines drop down to that main discharge line at the bottom of the screen and go over into one common discharge line into an oil separator and then up to the condenser. So we're going to skip over a lot of components in this and just go over the basics.
So discharge goes over to the condenser and it's coming back out the liquid line. It's coming back up and over and down to the receiver which, on this rack, is located underneath, but they can be remotely located as well. So all of these compressors share the same refrigerant charge and the same oil charge, and then it goes to the liquid dryer out of the receiver, and then this has a remote liquid header, which makes this much easier to film, but it doesn't have to be remote. It can be on top of the rack, so, as you can see, the liquid is going down to all the loads, the cases and walk-ins, and it's constantly feeding all of them.
There's no valves on the liquid, although some racks will have valves on the liquid behind that we got our suction lines coming back with our epr valves in this case, they're electronic and those are regulating the suction gas to achieve 100 run time in between defrost or At least that's the idea, and then it all ties back into this common suction header which goes down and around, and this is where it gets hard to film, but back behind the compressors, it's tied in the suction side, on each compressor. So that's your basic overview of the piping and the idea of the system. There's a lot more stuff going on to make it all work correctly. We could start here with the oil separator and oil reservoir, which are key components to be able to share the oil charge between three compressors.
So we need to get the oil out of the gas and back to the compressors, but we're going to go into detail on all the components and even more than we've talked about in this video. But this is just going to be a very basic overview. So the main idea is to keep compressors running as long as possible, share the refrigerant charge and the load and try to have a hundred percent run time between defrosts and there's different ways of accomplishing this, which we will get into in future videos. I'm gon na.
Try to keep them all short, but if there's any specific questions i'll do my best to answer them in the comment section. Thank you for watching thanks for watching our video. If you enjoyed it and got something out of it, if you wouldn't mind hitting the thumbs up button to like the video subscribe to the channel and click, the notifications bell to be notified when new videos come out, hvac school is far more than a youtube channel. You can find out more by going to hvacrschool.com, which is our website and hub for all of our content, including tech tips, videos, podcasts and so much more. You can also subscribe to the podcast on any podcast app of your choosing. You can also join our facebook group if you want to weigh in on the conversation yourself thanks again for watching you.
worked on racks all my life.
never once I regretted.
never worked on residential equipment and never will.
money is good cause there aren't many techs who can work on them while
everyone else is doing hvac. Service area Nepean??
I did racks about 7 years when l start my career l was lucky that l had a good knowledge of reading schematics and good electric background .Troubleshoot is 75% is electric and 25% mechanical of troubleshooting plus you have the BAS and rack controls . You only enough time due food spoil $$$ 4 hours was maximum from the time you get the call .
This is an eye opener for those of us that have never worked on rack refrigeration. Keep it coming! Good stuff!
Do they have like solenoid valves for each evap coil?
Thanks again for the videos!
🥃🥃🍺🍺🍺🎯🍿🏌🏻♀️
Stay safe.
Retired (werk'n)keyboard super tech. Wear your safety glasses!
Nice video more refrigeration please I want to expand my knowledge since I just started in the field Are you in Barrhaven ?
Racks are sweet but I personally prefer central systems with screw compressors or Mycom recips
Question = WHAT😵💫
As a commercial HVAC of 20 years I just what to say THANK YOU, for all of the late nights and overtime calls to keep our food cold!!!
I work around these every once in awhile. I'm a supermarket refrigeration tech and some of the stores we've got have parallel racks. A lot better than singles! Unless the charge blows lol.
Its all cool and stuff cool until there is a leak.
Make Rack Refrigeration great again! Let's go Brandon!
Will there be more videos on rack systems? Service area Orleans??
Thank you, been doing refrigeration for 27 years.
Never had the opportunity to work on those system….in fact must admit I’m a little intimidated of them, leaks must be a nightmare to deal with.
Looking forward to the other vids you’ll be posting on these systems
Master One question :
This is "parallel rack system", i.e common header for all Evaporator suction line and common reciever for all compressor.
What is "series rack system" ?
My idea : If there realy exist "series rack system", then it will be two or multi stage compression system.
Why can't I hit the like more than once😏
That's a weird looking air conditioner
So how do you deal with a compressor burn out, I have worked on many multi circuit A/C systems with parallel coms so we had to replace all of them on one circuit
👍👍
Perfect timing if I do say so myself, my employers are manufacturing chiller skids for Walmart coolers and they pipe in to Walmart’s existing rack system. Our skid contains a braze plate, special set of pumps, a set of eev’s, glycol feeder tank, and new set of controls. Trying to find more information about rack systems.
Walmart Boo! Nice Video!!!
Looking forward to all of this.